diff --git a/scripts/change_url b/scripts/change_url
index 572b377..6084121 100755
--- a/scripts/change_url
+++ b/scripts/change_url
@@ -16,7 +16,7 @@ source /usr/share/yunohost/helpers
 #=================================================
 ynh_script_progression --message="Stopping a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="stop" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="stop" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # MODIFY URL IN NGINX CONF
@@ -39,7 +39,7 @@ ynh_add_systemd_config
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="start" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # END OF SCRIPT
diff --git a/scripts/install b/scripts/install
index 1041919..4aaba2e 100755
--- a/scripts/install
+++ b/scripts/install
@@ -21,7 +21,7 @@ ynh_setup_source --dest_dir="$install_dir"
 mkdir -p "$install_dir/data"
 
 chmod -R 750 "$install_dir/data"
-chown -R $app:$app "$install_dir"
+chown -R "$app:$app" "$install_dir"
 
 ynh_secure_remove "$install_dir/client"
 ynh_secure_remove "$install_dir/server"
@@ -44,7 +44,7 @@ ynh_add_nginx_config
 
 ynh_add_systemd_config
 
-yunohost service add $app --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
+yunohost service add "$app" --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
 
 #=================================================
 # ADD A CONFIGURATION
@@ -52,7 +52,7 @@ yunohost service add $app --description="Open Source Push Notification Server" -
 ynh_script_progression --message="Adding a configuration file..." --weight=1
 
 ynh_add_config -t "ntfy.sh" -d "$install_dir/ntfy.sh"
-chown $app:$app "$install_dir/ntfy.sh"
+chown "$app:$app" "$install_dir/ntfy.sh"
 chmod u+x "$install_dir/ntfy.sh"
 
 #=================================================
@@ -62,14 +62,14 @@ chmod u+x "$install_dir/ntfy.sh"
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="start" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # ADD ADMIN
 #=================================================
 ynh_script_progression --message="Adding admin user..." --weight=1
 
-ynh_exec_as $app NTFY_PASSWORD="$password" $install_dir/ntfy.sh user add --role=admin $admin
+ynh_exec_as "$app" NTFY_PASSWORD="$password" "$install_dir/ntfy.sh" user add --role=admin "$admin"
 
 #=================================================
 # END OF SCRIPT
diff --git a/scripts/remove b/scripts/remove
index 6dc0d3b..3e175cb 100755
--- a/scripts/remove
+++ b/scripts/remove
@@ -9,10 +9,10 @@ source /usr/share/yunohost/helpers
 # REMOVE SYSTEMD SERVICE 
 #=================================================
 # Remove the service from the list of services known by YunoHost (added from `yunohost service add`)
-if ynh_exec_warn_less yunohost service status $app >/dev/null
+if ynh_exec_warn_less yunohost service status "$app" >/dev/null
 then
 	ynh_script_progression --message="Removing $app service integration..." --weight=1
-	yunohost service remove $app
+	yunohost service remove "$app"
 fi
 
 ynh_script_progression --message="Removing system configurations related to $app..." --weight=1
diff --git a/scripts/restore b/scripts/restore
index 1566077..695c64d 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -17,7 +17,7 @@ ynh_script_progression --message="Restoring the app main directory..." --weight=
 
 ynh_restore_file --origin_path="$install_dir"
 
-chown -R $app:www-data "$install_dir"
+chown -R "$app:www-data" "$install_dir"
 
 #=================================================
 # RESTORE SYSTEM CONFIGURATIONS
@@ -29,9 +29,9 @@ ynh_script_progression --message="Restoring system configurations related to $ap
 ynh_restore_file --origin_path="/etc/nginx/conf.d/$domain.d/$app.conf"
 
 ynh_restore_file --origin_path="/etc/systemd/system/$app.service"
-systemctl enable $app.service --quiet
+systemctl enable "$app.service" --quiet
 
-yunohost service add $app --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
+yunohost service add "$app" --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
 
 #=================================================
 # GENERIC FINALIZATION
@@ -40,7 +40,7 @@ yunohost service add $app --description="Open Source Push Notification Server" -
 #=================================================
 ynh_script_progression --message="Reloading NGINX web server and $app's service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="start" --log_path="/var/log/$app/$app.log"
 
 ynh_systemd_action --service_name=nginx --action=reload
 
diff --git a/scripts/upgrade b/scripts/upgrade
index aa1b779..d8dc85b 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -16,7 +16,7 @@ upgrade_type=$(ynh_check_app_version_changed)
 #=================================================
 ynh_script_progression --message="Stopping a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="stop" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="stop" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # "REBUILD" THE APP (DEPLOY NEW SOURCES, RERUN NPM BUILD...)
@@ -33,7 +33,7 @@ then
 	mkdir -p "$install_dir/data"
 
 	chmod -R 750 "$install_dir/data"
-	chown -R $app:$app "$install_dir"
+	chown -R "$app:$app" "$install_dir"
 
 	ynh_secure_remove "$install_dir/client"
 	ynh_secure_remove "$install_dir/server"
@@ -48,7 +48,7 @@ ynh_add_nginx_config
 
 ynh_add_systemd_config
 
-yunohost service add $app --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
+yunohost service add "$app" --description="Open Source Push Notification Server" --log="/var/log/$app/$app.log"
 
 #=================================================
 # RECONFIGURE THE APP (UPDATE CONF, APPLY MIGRATIONS...)
@@ -66,7 +66,7 @@ ynh_script_progression --message="Updating simple command wrapper..." --weight=1
 
 ynh_add_config --template="ntfy.sh" --destination="$install_dir/ntfy.sh"
 
-chown $app:$app "$install_dir/ntfy.sh"
+chown "$app:$app" "$install_dir/ntfy.sh"
 chmod u+x "$install_dir/ntfy.sh"
 
 #=================================================
@@ -74,7 +74,7 @@ chmod u+x "$install_dir/ntfy.sh"
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="start" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # END OF SCRIPT